Current geospatial databases are primarily sources for outdoor two dimensional (2D) maps. In recent years there has been an explosion of mapping applications on the web such as GOOGLE MAPS and BING MAPS. These websites give the public access to huge amounts of geographic data. Some of them, like GOOGLE MAPS, expose an application programming interface “API” that enables users and developers to create custom applications. These toolkits commonly offer street maps, aerial/satellite imagery, geo-coding, searches, and routing functionality.
So far, the only proven method to build a great digital mapping system is to employ a large number of people to capture the necessary data. GOOGLE, with its pool of “Street View” mapping cars, is a successful example of a company that has been able to efficiently manage the big labor required for this process.
The steps required to create an accurate global database of outdoor maps include combining maps from various sources, manually correcting the data layer using the satellite images, and using alternative sources of data to verify the accuracy of map data. GOOGLE has a map creating tool, called Atlas, used by thousands of GOOGLE employees to hand correct the maps. They have access to the images from the GOOGLE Street View cars that use global positioning system (GPS) data to collect geo-referenced imagery so they know precisely where the roads are located.
A growing number of companies are now creating maps of indoor spaces, e.g. malls, airports, hospitals, and museums. Commercial and enterprise applications require indoor maps to support accurate location calculations, indoor routing, location display, asset management, location sharing, and geo-tagging.
The process of building indoor maps is different from the process of building outdoor maps. Neither satellite imagery nor GPS traces for referencing the images are available for indoor spaces, therefore alternative methods are needed to create indoor maps in a large scale.
GOOGLE has moved into mapping indoor spaces and has launched indoor maps in eight countries for more than 10,000 venues. It has digitalized maps of malls, airports and museums and has included them in GOOGLE MAPS. It has also launched a tool for the public to upload floor plans. GOOGLE has also started to collect images of indoor venues similar to those it collected for Street View using a multi-camera imaging tool they call Trekker.
GOOGLE's approach to creating maps from building blueprints or measuring spaces has some major challenges. For example, it is very labor intensive and difficult to scale. Although GOOGLE has made great progress, it has only covered a small fraction of indoor locations and a massive number of buildings are waiting to be mapped and entered into mapping and navigation systems. Creating maps is very challenging, however, a bigger challenge is to maintain and update these maps as they change over time. For example, NOKIA collects 400 data points for each road segment, and they estimate that 5 to 20 percent of these points change each year. Due to all these changes, NOKIA can never stop collecting new data from the physical world to hand correct maps. NOKIA on average makes 2.4 million map changes every day. The same maintenance problem applies to indoor maps.
A different type of indoor mapping process is disclosed in U.S. Patent Publication No. 2007/0185681, hereinafter “McKitterick.” McKitterick discloses a system for mapping a room or a series of rooms by having a person (such as a soldier) sweep a range-finder around the walls of the room, and perhaps mark one or more doors and windows (such as with an X and an O, respectfully). The range-finder measures the distance from the range-finder to the walls. At the same time, information about the attitude and position of the range-finder is obtained from a six-axis inertial sensor attached to the range-finder. Maps of buildings are created by connecting individual room reconstructions collected by the range-finder using a combination of 1) knowledge of building constructs, 2) the path traveled by mapping the person as the person moves from room to room, and 3) the location of doors connecting adjacent rooms.